During petroleum production operations, the thermophysical properties, such as thermal conductivity, specific heat, and viscosity of the downhole hydrocarbon fluid often affect production efficiency and cost. High viscosity hydrocarbon fluid production may require the application of external heat to reduce the viscosity of the fluid and enable fluid transport from one place in the reservoir to the well location. Efficiency of production more or less depends upon the external heating power and thermal energy transport within a limited time interval. Higher thermally conductive hydrocarbon fluid can effectively transport the thermal energy further than low thermally conductive fluids. It is desirable to be able to measure thermal conductivity properties during wireline logging services and during production processes. The formation fluid thermal conductivity properties that are obtained can be used for wellbore completion, production efficiency control, and optimization.
The thermal conductivity properties of the downhole formation fluids varies with pressure, temperature, and chemical composition or molecular weight; the measurement of thermal conductivity can therefore be used to identify formation fluids. Downhole formation fluids at different geometric locations may also have different thermophysical properties regarding viscosity, density, thermal conductivity, specific heat capacity, and mass diffusion. Each of these properties can at least partially govern transportation and mobility of crude oils, including high viscosity crude oils, and can consequently impact the recovery process of the crude oils.
Reservoir hydrocarbon fluids may have similar thermal conductivity properties but different viscosity, density, compressibility, mass diffusivity, and specific heat capacity. Knowing thermal conductivity and other thermophysical properties of the hydrocarbon fluid can at least partially enable optimization of a well completion design and crude oil production processes. Presently, the thermal conductivity property of the reservoir or downhole hydrocarbon fluid is collected and analyzed in a surface laboratory with a PVT method, which may take days or even months. This PVT method tends to reduce the accuracy of any measurements due to the passage of time since collection, and environmental changes at the collection point(s) which can occur over time. In-situ detection of these thermophysical properties can improve accuracy of measurement, improve well completion design, crude oil production processes, and production efficiency.